Fix missing EvalPlanQual recheck for TID scans - Mailing list pgsql-hackers

From David G. Johnston
Subject Fix missing EvalPlanQual recheck for TID scans
Date
Msg-id CAKFQuwZjhJv_hRO=7V_6XhCQ-xD2ZuCL+4_giWNJAeNDhBd5AA@mail.gmail.com
Whole thread Raw
In response to Re: Fix missing EvalPlanQual recheck for TID scans  (Chao Li <li.evan.chao@gmail.com>)
List pgsql-hackers
On Sunday, September 14, 2025, Chao Li <li.evan.chao@gmail.com> wrote:

It says that UPDATE will only find target rows that were committed as of the command start time. I think the statement implies that an “update” statement will never update a “future” tuple.

It will indeed see a future physical tuple so long as the logical row that said tuple refers to already was committed, and it found the corresponding past physical tuple.

Admittedly, I’m unclear on how exactly the system communicates/understands that the past and future physical tuples refer to same logical row reliably.  In the docs, one is left to assume that feature just works.

David J.

pgsql-hackers by date:

Previous
From: Naga Appani
Date:
Subject: Re: [Proposal] Expose internal MultiXact member count function for efficient monitoring
Next
From: "David G. Johnston"
Date:
Subject: Re: Fix missing EvalPlanQual recheck for TID scans